refactor: simplify module platform — drop custom autoloader, layout_capabilities indirection, and absolute template paths

- Replace ModuleAutoloader with Composer ClassLoader (addPsr4 via spl_autoload_functions)
- Eliminate layout_capabilities mapping; UI slots reference ability strings directly
- Resolve relative template paths in ModuleRegistry instead of baking __DIR__ into manifests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

modules/addressbook/module.php

@@ -32,8 +32,8 @@ return [
                 'label' => 'Address book',
                 'icon' => 'bi-people',
                 'href' => 'address-book',
-                'permission' => 'can_view_address_book',
-                'panel_template' => __DIR__ . '/templates/aside-people-panel.phtml',
+                'permission' => 'addressbook.view',
+                'panel_template' => 'templates/aside-people-panel.phtml',
                 'details_storage' => 'aside-people-tenant',
                 'details_open_active' => true,
                 'order' => 110,
@@ -44,7 +44,7 @@ return [
                 'key' => 'address-book',
                 'label' => 'Address book',
                 'base_url' => 'address-book',
-                'permission' => 'can_view_address_book',
+                'permission' => 'addressbook.view',
                 'order' => 110,
             ],
         ],
@@ -54,7 +54,7 @@ return [
                 'type' => 'link',
                 'label' => 'View in address book',
                 'href' => 'address-book/view/{user_uuid}',
-                'permission' => 'can_view_address_book',
+                'permission' => 'addressbook.view',
                 'order' => 110,
             ],
         ],
@@ -64,10 +64,6 @@ return [
         \MintyPHP\Module\AddressBook\AddressBookAuthorizationPolicy::class,
     ],
 
-    'layout_capabilities' => [
-        'can_view_address_book' => 'addressbook.view',
-    ],
-
     'search_resources' => [
         \MintyPHP\Module\AddressBook\Providers\AddressBookSearchProvider::class,
     ],